Process for renovating or resharpening recording styli



Jan. 26, 1954 c. F. STRANDBERG 2,667,434

PROCESS FOR RENOVATING OR RESHARPENING RECORDING STYLI Filed Jan. 18, 1950 INVENTOR Charla; F. Etr a n'flh erg ATTORNEY Patented Jan. 26, 1954 UNITED? STATES PROCESS-FOR RENOVATING OR RESHARB- ENINGRECORDING STYLI Charles F. Strandberg, Greensboro, N. C.

AppllcationdanuarylS, 1950, Serial No. 139,339,

40mins. (01. 134-42),

The invention relates to aprocess for renovating or resharpening recording styli.

Sapphires are'at present widely used as styli for recording on aluminum base records or disks. Such styli are quite expensive and-in accordance with the present practice mustbe frequently replaced or resharpened to avoid the production of unpleasant sounds which are frequently referred to as hissing, squealing, scratching and thelike. The resharpening of *such styli as at present practiced is anexpensive'and unsatisfactoryprocedure which results in serious wear on the tip.

It'has been generally considered that these unpleasant noises are due to wear, breakage or chipping of'the styli by reasonof their contact with the aluminum baseportion of the recording disks; Contrary to the-accepted view I have found thatin most caseswhere-these'undesin able-noises occur the sapphire itself; whichis a very-hard stone having a hardness approaching that of the diamond, has not been permanently impaired,- but instead has become coated with or has its point embedded in tiny pieces-of aluminum collected from the base. It is-thesetiny pieces of irregularly shaped aluminum which in the vast majority of cases result in defective styli and produce extreme levels of noises in instantaneous disk recording. Normally the record groove wall is polished by burnishing facets, which are extremely narrow, having a maximum width of about 0.001inch, and which extend farbeyond that portion ofthe sapphire which isfunctional, namely the tip, and-which portion actually makes the groove.

By removing the aluminum particles from a used sapphire stylus I have found that contrary to previous views prevailing in the industry the sapphire itself was undamaged and the stylus restored, renovated or sharpened so that it could again be used for recording purposes without the production of unpleasant sounds. Attempts have been made to mechanically or physically remove the aluminum particles, as, for example, by the use of a cloth having the proper abrasive characteristics and of suflicient softness so as to remove the aluminum without damaging the sapphire. While these efforts have been successful, in that it is possible to remove the aluminum particles and thus restore the usefulness of the styli, nevertheless the mechanical or physical cleaning of the stylus has been found to be relatively inefiicient, and in accordance with my invention chemical cleaning is employed, which treatment has proved to be very successful in actual practice.

Various reagents may be employed, including 2' suitable acids, bases. and salts for dissolving. the aluminum, and as, examples hydrochloric .acid,

sodium hydroxide, potassium hydroxide, sodium. carbonate. and potassium. carbonate may be mentioned byway of. illustration rather than by way of limitation. The strength. of,v these reagents may be varied. widely without, departing, from my invention, and reagents of any strength capable of dissolving the aluminum may be employed. As a specific example, sodium hydroxide of 40% concentration ,hasbeen successfully employed. The .reagentymay be arbitrarily colored red foreasy identification.

In order to simplify and. standardize thev chemical treatment 'oflthe sapphire styli I have.

devised an improved apparatus whereby the de-,

gree of immersion of the stylusintc the reagent,

may be regulatedgso as, to permitdipping the sapphire portionpf the stylus thejreagent while preventing contact of the reagentjwith the shank or stem of the stylus, which latter portion is generally formed ofbrass or aluminum or other metal which would be dama ed .bycontact with the cleaning reagent.

the accompanying drawings, in which Fig, 1 is a sideelevation,showing 'a..sapphire..

tip, cleaning instrumentembodying my invention;

Fig. 2 is a plan view on a smallerscale than Fig. 1 showing the base or pedestal whi h supports the cleaning instrument; and

Fig. 3 is a vertical sectionjon alarger scale than Fig. 1 showing the stylus holding chuck of the cleaning instrumenuwith a, stylus supported therein.

Referring to the drawings, 10 denotes a wooden pedestal or block having a central depression or well I I therein, in which the bottom of a reagent containing tube or vial I2 is seated. The vial is preferably of transparent material, such as glass, plastic or the like, and may be provided with a suitable stopper l3 of rubber or the like having a central passage [4 extending therethrough, through which may be passed a stem i5 threaded through a substantial portion of its length and carrying at its lower end a stylus holding chuck I6 preferably formed of plastic material, such as polystyrene. A pair of nuts I? and [8 are provided at the top and bottom of the rubber stopper l3, said nuts having internal threads coacting with the threads of the chuck holding stem, and permitting the same to be raised or lowered by rotation of a suitable wing nut or the like [9 secured at the top of the stem Hi.

The polystyrene chuck I6 is provided with an Asuitable device for accomplishing this purpose is disclosedfin'.

axial socket 20 extending upwardly therethrough, which socket may be lined with rubber cushioning material to yieldingly hold a stylus shank 2|, the tip 22 of which projects beyond the socket. It will be obvious that the metal shank of the stylus will be protected from the reagent in the vial l2 by reason of its insertion into the socket 20, although normally the lower end of the chuck will not extend materially below the surface of the reagent liquor.

If desired a diametrical saw cut may be provided at the lower end of the chuck intersecting the socket 20 in order to augment the gripping action of the socket on the stylus shank.

In operation the vial l2 may be filled to any desired level with a suitable stylus tip cleansing reagent, such as 40% sodium hydroxide. The stem of the stylus to be cleaned is fitted into the socket 211 in the chuck it and the stopper l3 carrying the stem l5 with the chuck 1'5 at the lower end thereof is then inserted in the neck of the vial and the position of the chuck 16 adjusted by turning the wing nut I9 until the stylus tip to be cleaned is immersed in the cleaning fluid and the lower end of the chuck preferably just touches the surface of the cleaning reagent. The chuck I6 is unaffected by the reagent in the vial owing to the nature of the material of which it is formed and the stylus stem, which may be of metal, is protected within the socket 20 from contact with the reagent. The stylus tip remains immersed in the cleaning fluid within the vial until such time as the aluminum adhering to the stylus tip is dissolved by the reagent, whereupon the stopper l3 carrying with it the stem l5, chuck it and the renovated or resharpened stylus is withdrawn from the mouth of the vial and the stylus removed from the chuck. The resharpened stylus is then ready for renewed use.

The invention has been described in detail for the purpose of illustration, but it will be obvious thatmany variations and modifications may be resorted to without departing from the spirit of with an additional well I! to receive a slightly smaller vial 12' in which the reagent is originally supplied and from which the desired quantity of the reagent may be poured into the larger vial I2.

I claim:

1. A methodofresharpening the sapphire tips of recording styli which have become dull by reason of the adherence to said tips of portions of aluminum gathered from contact with the base portions of recording disks or the like, which aluminum particles from the tips by immersion in a chemical bath reactive with the aluminum particles but non-reactive with sapphire.

3. A method of resharpening the sapphire tips of recording styli which have become dull by reason of the adherence of said tips of portions of aluminum gathered from contact with the base portions of recording disks or the like, which comprises chemically removing the adhering aluminum particles from the tips by immersion in a bath of sodium hydroxide.

4. A method of resharpening the sapphire tips of recording styli which have become dull by reason of the adherence to said tips of portions of aluminum gathered from contact with the base portions of recording disks or the like, which the invention. Thus, while in the foregoing description sapphire styli have been referred to, the invention in its broadest aspects is applicable to the renovating or resharpening of other types of styli the tips of which may have become dull by reason of the presence thereon of particles of soft metal, such as aluminum, on account of contact between such styli tips and the metal base portions of the recording disks.

In addition to the well II in which the vial I2 is seated the pedestal or block l0 may be provided comprises chemically removing the adhering aluminum particles from the tips by immersion in a chemical bath reactive with the aluminum particles but non-reactive with sapphire and regulating the degree of immersion.

CHARLES F. STRANDBERG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 357,860 Sawyer Feb. 15, 1887 674,254 Arthur May 14, 1901 1,767,370 Kehn June 24, 1930 2,156,594 Lester May 2, 1939 2,405,101 Truesdell July 30, 1946 

1. A METHOD OF RESHARPENING THE SAPPHIRE TIPS OF RECORDING STYLI WHICH HAVE BECOME DULL BY REASON OF THE ADHERENCE TO SAID TIPS OF PORTIONS OF ALUMINUM GATHERED FROM CONTACT WITH THE BASE PORTIONS OF RECORDING DISKS OR THE LIKE, WHICH COMPRISES CHEMICALLY REMOVING THE ADHERING ALUMINUM PARTICLES FROM THE TIPS BY APPLICATION TO THE TIP OF A CHEMICAL WHICH IS REACTIVE WITH THE ALUMINUM PORTIONS BUT IS NON-REACTIVE WITH SAPPHIRE. 